33389 datasheet(43/49 Pages) FREESCALE

43 / 49 page

Analog Integrated Circuit Device Data

Freescale Semiconductor

33389

TYPICAL APPLICATIONS

Figure 25. Typical Application Schematic 2

The SBC offers several capabilities to help users debug

their application.

• External bias of V1 and reset pin

• Turn OFF software watchdog in the Stand-by mode

• Special debug samples with software watchdog disable at

power-up (contact local Motorola representative)

DEBUG AND PROGRAM DOWNLOAD INTO FLASH

MEMORY

While the SBC is powered, it enters Normal Request mode

and expects during the 75 ms time period in the NR mode, an

SPI trigger word (to enter Normal mode and select the

watchdog time period). If this does not occur, the SBC enters

the Sleep mode and turns off V1.

When the software is debugged, and when using

development tools, it is not always easy to make sure these

events happen properly. It is thus possible to externally

power the V1 line with an external 5.0 V supply, and to force

the Reset pin to V1 or to and external 5.0 V. These can be

done at nominal voltage and temperature. By doing this, 5.0

V is provided to the MCU VDD and reset lines.

Under this condition the SBC is not operational. However,

the reset pin is pulled low and is sinking 5 mA to ground. This

means, the external circuitry driving reset must have a

current capability higher than 5 mA in order to drive the reset

in the high-state.

DISABLE OF SOFTWARE WATCHDOG IN STAND-

BY MODE

The software watchdog can be disable in Stand-by mode

only. In order to disable it the following operation must be

done:

• Write to MCR register–data 011 (bit 2, bit 1, bit 0)

• Write to MCVR register–data 011 (bit 2, bit 1, bit 0)

Then the SBC enters the Stand-by mode without software

watchdog. However the V2 can not be turn on, and the CAN

cell can not be used.

(Wake-up input linked to peripheral circuits: (ex: low speed CAN or LIN transceivers).

VBAT

RST

INT

MISO

MOSI

SCK

CANH

CANL

RTL

RTH

Rp0

GND

CAN 1

SPI

VDD

INT

RESET

Auxiliary 5V

Auxiliary 12V

Rs0

CL0

Ignition

CAN bus # 1

CANH

CANL

RTL

RTH

CAN bus # 2

GND

INH

MC33388

LIN

LIN bus

GND

INH

MC33399

+12V

VBAT

VDD

VSUP

CAN 2

SCI

SPI bus

Tx/Rx

33389

33389 Datasheet(PDF) 43 Page - Freescale Semiconductor, Inc

33389 Datasheet(HTML) 43 Page - Freescale Semiconductor, Inc

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49

Datasheet Download

Link URL